Reactions of Pyridyl Side-Chain-Functionalized Cyclopentadienes

Thermal treatment of the pyridyl side-chain-functionalized cyclopentadienes with Fe(CO)5 and Ru3(CO)12 gave different intramolecular C−H activated p...
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Organometallics 2006, 25, 307-310

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Notes Reactions of Pyridyl Side-Chain-Functionalized Cyclopentadienes with Metal Carbonyl: Intramolecular C-H Activation of Pyridine Dafa Chen, Ying Li, Baiquan Wang,* Shansheng Xu, and Haibin Song State Key Laboratory of Elemento-Organic Chemistry, College of Chemistry, Nankai UniVersity, Tianjin 300071, People’s Republic of China, and State Key Laboratory of Organometallic Chemistry, Chinese Academy of Sciences, Shanghai 200032, People’s Republic of China ReceiVed August 7, 2005 Summary: Thermal treatment of the pyridyl side-chain-functionalized cyclopentadienes with Fe(CO)5 and Ru3(CO)12 gaVe different intramolecular C-H actiVated products, in addition to the normal dinuclear metal complexes. Reactions of the dinuclear metal complexes with I2 also gaVe different metal iodide complexes.

Introduction The chemistry of cyclopentadienyl metal complexes containing a donor-functionalized side chain has been receiving much attention.1 For the pyridyl side-chain-functionalized cyclopentadienyl ligands, the nitrogen atom can act as a good twoelectron donor site and can coordinate to a variety of metals, and intramolecular coordination to a Lewis acidic metal center or construction of oligonuclear metal complexes should be easily achieved with them.1a,2 In this contribution we report the reactions of pyridyl side-chain-functionalized cyclopentadienes with Fe(CO)5 and Ru3(CO)12, which gave different intramolecular C-H activated products, in addition to the normal bis(cyclopentadienyl) dinuclear metal complexes. The reactions of the dinuclear metal complexes with I2 were also found to give different metal iodide complexes.

Results and Discussion

Figure 1. ORTEP diagram of 3. Thermal ellipsoids are shown at the 30% level. Selected bond lengths [Å] and angles [deg]: Fe(1)-Fe(2) 2.577(2), Fe(1)-C(1) 1.861(7), Fe(1)-N(1) 1.955(6), Fe(2)-C(1) 2.153(7), Fe(2)-C(13) 1.980(7), N(1)-Fe(1)-Fe(2) 72.34(16), C(13)-Fe(2)-Fe(1) 71.30(19), C(13)-N(1)Fe(1) 106.4(5), N(1)-C(13)-Fe(2) 106.5(5). Scheme 1

Upon thermal treatment of ligand 1 with Fe(CO)5 in refluxing toluene, the intramolecular C-H activated product 3 (1%) and the diiron complex 4 (37%) were obtained (Scheme 1). The 1H NMR spectrum of 3 shows three groups of peaks for the pyridyl * Corresponding author. Fax: 86-22-23502458. E-mail: bqwang@ nankai.edu.cn. (1) For recent reviews see: (a) Jutzi, P.; Siemeling, U. J. Organomet. Chem. 1995, 500, 175. (b) Jutzi, P.; Redeker, T. Eur. J. Inorg. Chem. 1998, 663. (c) Mu¨ller, C.; Vos, D.; Jutzi, P. J. Organomet. Chem. 2000, 600, 127. (d) Siemeling, U. Chem. ReV. 2000, 100, 1495. (e) Butenschon, H. Chem. ReV. 2000, 100, 1527. (f) Fischer, P. J.; Krohn, K. M.; Mwenda, E. T.; Young, V. G., Jr. Organometallics 2005, 24, 1776. (2) (a) Chen, S. S.; Lei, Z. P.; Wang, J. X.; Wang, R. J.; Wang, H. G. Sci. China (Ser. B) 1994, 37, 788. (b) van den Hende, J. R.; Hitchcock, P. B.; Lappert, M. F.; Nile, T. A. J. Organomet. Chem. 1994, 472, 79. (c) Siemeling, U.; Vorfeld, U.; Neumann, B.; Stammler, H. G. Chem. Ber. 1995, 128, 481. (d) Plenio, H.; Burth, D. Organometallics 1996, 15, 4054. (e) Ziniuk, Z.; Goldberg, I.; Kol, M. J. Organomet. Chem. 1997, 545546, 441. (f) Blais, M. S.; Chien, J. C. W.; Rausch, M. D. Organometallics 1998, 17, 3775. (g) Schliessburg, C.; Thiele, K.-H.; Lindner, B.; Bru¨ser, W. Z. Anorg. Allg. Chem. 2000, 626, 741. (h) Dreier, T.; Frohlich, R.; Erker, G. J. Organomet. Chem. 2001, 621, 197. (i) Zhang, H.; Ma, J.; Qian, Y.; Huang, J. Organometallics 2004, 23, 5681.

protons at 6.81, 6.64, and 6.46 ppm, two triplets for the cyclopentadienyl protons at 5.19 and 3.72 ppm, and one singlet for the methylene and methyl protons at 2.53 and 1.26 ppm, respectively. The IR spectrum of 3 shows three terminal and two bridging carbonyl absorptions at 2042, 1973, 1938, and 1839, 1775 cm-1. X-ray diffraction analysis shows that in 3 one iron atom is coordinated with an η5-cyclopentadienyl and an intramolecular nitrogen atom of the pyridyl; the other iron atom is bonded to the R-C of the pyridyl and coordinated with three carbonyls (Figure 1). Complex 3 is the first example of a cyclometalated complex of iron containing a heterocyclic donor atom, although cyclometalated derivatives of ruthenium and

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Notes

Figure 2. ORTEP diagram of 7. Thermal ellipsoids are shown at the 30% level. Selected bond lengths [Å] and angles [deg]: Ru(1)-Ru(2) 3.0131(10), Ru(2)-Ru(3) 2.9998(9), Ru(1)-N(1) 2.086(3), Ru(2)-C(30) 2.063(4), Ru(2)-C(16) 2.099(4), Ru(3)-N(2) 2.077(3), N(1)Ru(1)-Ru(2) 66.19(9), C(30)-Ru(2)-Ru(3) 67.13(13), C(16)-Ru(2)-Ru(1) 67.10(11), Ru(3)-Ru(2)-Ru(1) 99.96(3), N(2)-Ru(3)Ru(2) 65.73(10), C(16)-N(1)-Ru(1) 114.8(3), C(30)-N(2)-Ru(3) 114.6(3), N(1)-C(16)-Ru(2) 111.8(3), N(2)-C(30)-Ru(2) 112.5(3). Scheme 2

osmium are relatively well-known.3 Similarly, reaction of ligand 2 with Fe(CO)5 gave the C-H activated product 5 (5%) and the diiron complex 6 (52%). When ligand 1 reacted with Ru3(CO)12 in refluxing xylene, the intramolecular C-H activated product 7 (7%) and the diruthenium complex 8 (24%) were obtained (Scheme 2). The 1H NMR spectrum of 7 shows five groups of peaks for the pyridyl protons at 7.44, 7.17, 6.86-6.75, 6.68, and 6.17 ppm, seven groups of peaks for the cyclopentadienyl protons at 5.46, 5.31, 5.27, 5.18, 4.47, 4.44, and 4.33 ppm, four groups of peaks for the methylene protons at 2.73, 2.68, 2.62, and 2.57 ppm, and one singlet for the methyl protons at 1.54 ppm, indicating that complex 7 contains two ligands in a molecule. The IR spectrum of 7 shows only four terminal carbonyl absorptions at 2004, 1950, 1933, and 1910 cm-1. X-ray diffraction analysis shows that complex 7 contains a Ru(CO)Ru(CO)2Ru(CO) unit, coordinated with two ligands (Figure 2). The Ru(1) and Ru(3) are coordinated each with an η5-cyclopentadienyl, an intramolecular nitrogen atom of the pyridyl, and a carbonyl. The Ru(2) is bonded with two R-C of the pyridyls and coordinated with two carbonyls. There are many examples of ruthenium clusters with orthometalated pyridyl ligands.3-5 The Ru-Ru distances [3.0131(10), 2.9998(9) Å] in 7 are much longer, while the Ru-C(pyridyl) [2.099(4), 2.063(4) Å] and Ru-N [2.086(3), 2.077(3) Å] distances are generally shorter than those in these complexes (2.715-2.921, 2.04-2.19, and 2.07-2.14 Å, respectively).4,5 Similarly, reaction of ligand 2 with Ru3(CO)12 gave the C-H activated product 9 (6%) and the diruthenium complex 10 (31%). When the dinuclear metal complexes 4, 6, 8, and 10 reacted with I2, different metal iodide complexes 11-14 were obtained (3) Constable, E. C. Polyhedron 1984, 3, 1037.

Scheme 3

(Scheme 3). Complexes 11 and 12 are the intramolecular nitrogen-coordinated ionic complexes (Figure 3), while complexes 13 and 14 are the intramolecular nitrogen-coordinated Ru-I complexes (Figure 4).

Experimental Section General Considerations. 1H NMR spectra were recorded on a Bruker AV300 or Bruker AC-P200, while IR spectra were recorded as KBr disks on a Nicolet 5DX FT-IR spectrometer. Elemental analyses were performed on a Perkin-Elmer 240C analyzer. Ligands 1 and 2 were prepared according to literature methods.2a (4) (a) Foulds, G. A.; Johnson, B. F. G.; Lewis, J. J. Organomet. Chem. 1985, 294, 123. (b) Foulds, G. A.; Johnson, B. F. G.; Lewis, J. J. Organomet. Chem. 1985, 296, 147. (c) Eisenstadt, A.; Giandomenico, C. M.; Frederick, M. F.; Laine, R. M. Organometallics 1985, 4, 2033. (d) Bruce, M. I.; Humphrey, M. G.; Snow, M. R.; Tiekink, E. R. T.; Wallis, R. C. J. Organomet. Chem. 1986, 314, 311. (e) Fish, R. H.; Kim, T.-J.; Stewart, J. L.; Bushweller, J. H.; Rosen, R. K.; Dupon, J. W. Organometallics 1986, 5, 2193. (f) Cockerton, B. R.; Deeming, A. J. J. Organomet. Chem. 1992, 426, C36. (g) Cifuentes, M. P.; Humphrey, M. G.; Skelton, B. W.; White, A. H. Organometallics 1993, 12, 4272. (h) Cifuentes, M. P.; Humphrey, M. G.; Skelton, B. W.; White, A. H. J. Organomet. Chem. 1994, 466, 211. (i) Cifuentes, M. P.; Humphrey, M. G.; Skelton, B. W.; White, A. H. J. Organomet. Chem. 1996, 513, 201. (j) Kabir, S. E.; Siddiquee, T. A.; Rosenberg, E.; Smith, R.; Hursthouse, M. B.; Malik, K. M. A.; Hardcastle, K. I.; Visi, M. J. Cluster Sci. 1998, 9, 185. (k) Cauzzi, D.; Graiff, C.; Massera, C.; Predieri, G.; Tiripicchio, A. Eur. J. Inorg. Chem. 2001, 721. (l) Cabeza, J. A.; da Silva, I.; del Rı´o, I.; Martı´nez-Me´ndez, L.; Miguel, D.; Riera, V. Angew. Chem., Int. Ed. 2004, 43, 3464. (5) (a) Cabeza, J. A. Eur. J. Inorg. Chem. 2002, 1559, and references therein. (b) Cabeza, J. A.; del Rı´o, I.; Garcı´a-Granda, S.; Riera, V.; Sua´rez, M. Organometallics 2002, 21, 2540. (c) Cabeza, J. A.; del Rı´o, I.; Garcı´aGranda, S.; Riera, V.; Sua´rez, M. Organometallics 2002, 21, 5055. (d) Cabeza, J. A.; del Rı´o, I.; Garcı´a-A Ä lvarez, P.; Riera, V.; Sua´rez, M.; Garcı´aGranda, S. Dalton Trans. 2003, 2808. (e) Cabeza, J. A.; del Rı´o, I.; Riera, V.; Sua´rez, M.; Garcı´a-Granda, S. Organometallics 2004, 23, 1107. (f) Cabeza, J. A.; del Rı´o, I.; Garcı´a-Granda, S.; Riera, V.; Sua´rez, M. Organometallics 2004, 23, 3501.

Notes

Figure 3. ORTEP diagram of 12. Thermal ellipsoids are shown at the 30% level.

Figure 4. ORTEP diagram of 13. Thermal ellipsoids are shown at the 30% level. Reaction of 1 with Fe(CO)5. A solution of 4.96 g (24.92 mmol) of ligand 1 and 5.00 mL (37.19 mmol) of Fe(CO)5 in 30 mL of toluene was refluxed for 7 h. The solvent was removed under reduced pressure, and the residue was placed in an Al2O3 column. Elution with CH2Cl2/petroleum ether developed a red band and with acetone developed another red band. The first red band gave 0.095 g (1%) of 3 as red crystals, and the second red band yielded 2.875 g (37%) of 4 as dark red crystals. 3: mp 203 °C (dec). Anal. Calcd for C19H15Fe2NO5: C, 50.82; H, 3.37; N, 3.12. Found: C, 50.68; H, 3.34, N, 3.30. 1H NMR (CDCl3) δ: 6.81 (t, 1H, C5H3N), 6.64 (d, J ) 7.57 Hz, 1H, C5H3N), 6.46 (d, J ) 7.49 Hz, 1H, C5H3N), 5.19 (t, 2H, C5H4), 3.72 (t, 2H, C5H4), 2.53 (s, 2H, CH2), 1.26 (s, 6H, Me2C). IR (νCO, cm-1): 2042(s), 1973(s), 1938(m), 1839(m), 1775(s). 4: mp 133-134 °C. Anal. Calcd for C32H32Fe2N2O4: C, 61.96; H, 5.20; N, 4.52. Found: C, 61.88; H, 4.92, N, 4.55. 1H NMR (CDCl3) δ: 8.46 (d, J ) 4.68 Hz, 2H, C5H4N), 7.46 (t, 2H, C5H4N), 7.07 (t, 2H, C5H4N), 6.81 (d, J ) 7.81 Hz, 2H, C5H4N),

Organometallics, Vol. 25, No. 1, 2006 309 4.72 (t, 4H, C5H4), 4.10 (t, 4H, C5H4), 2.98 (s, 4H, CH2), 1.41 (s, 12H, Me2C). IR (νCO, cm-1): 1934(s), 1898(m), 1763(s), 1728(m). Reaction of 2 with Fe(CO)5. Using a procedure similar to that described above, reaction of 2 with Fe(CO)5 gave 5 and 6 in 5% and 52% yields, respectively. 5: mp 200 °C (dec). Anal. Calcd for C22H19Fe2NO5: C, 54.03; H, 3.92; N, 2.86. Found: C, 54.09; H, 3.76, N, 2.91. 1H NMR (CDCl3) δ: 6.82 (t, 1H, C5H3N), 6.64 (d, J ) 7.33 Hz, 1H, C5H3N), 6.49 (d, J ) 7.59 Hz, 1H, C5H3N), 5.20 (s, 2H, C5H4), 3.72 (s, 2H, C5H4), 2.58 (s, 2H, CH2), 1.77-1.41(m, 10H, (CH2)5C). IR (νCO, cm-1): 2042(s), 1985(s), 1970(s), 1878(m), 1787(s). 6: mp 162-163 °C. Anal. Calcd for C38H40Fe2N2O4: C, 65.15; H, 5.76; N, 4.00. Found: C, 65.02; H, 5.68, N, 4.16. 1H NMR (CDCl3) δ: 8.38 (d, J ) 4.68 Hz, 2H, C5H4N), 7.36 (t, 2H, C5H4N), 7.00 (t, 2H, C5H4N), 6.56 (d, J ) 7.76 Hz, 2H, C5H4N), 4.55 (t, 4H, C5H4), 4.02 (t, 4H, C5H4), 3.08 (s, 4H, CH2), 1.90-1.40 (m, 20H, (CH2)5C). IR (νCO, cm-1): 1942(s), 1914(m), 1775(s), 1752(m). Reactions of 1 and 2 with Ru3(CO)12. Using a procedure similar to that described above, reactions of 1 and 2 with Ru3(CO)12 under refluxing xylene for 12 h gave 7, 8, and 9, 10 in 7%, 24%, and 6%, 31% yields, respectively. 7: mp 133 °C (dec). Anal. Calcd for C32H30N2O4Ru3: C, 47.46; H, 3.73; N, 3.46. Found: C, 47.50; H, 3.71, N, 3.45. 1H NMR (CDCl3) δ: 7.44 (d, J ) 7.50 Hz, 1H, C5H3N), 7.17 (t, 1H, C5H3N), 6.86-6.75 (m, 2H, C5H3N), 6.68 (d, J ) 7.50 Hz, 1H, C5H3N), 6.17 (d, J ) 7.50 Hz, 1H, C5H3N), 5.46 (s, 1H, C5H4), 5.31 (s, 1H, C5H4), 5.27 (s, 1H, C5H4), 5.18 (s, 1H, C5H4), 4.47 (s, 1H, C5H4), 4.44 (s, 1H, C5H4), 4.33 (m, 2H, C5H4), 2.73 (s), 2.68 (s), 2.62 (s), 2.57 (s) (total, 4H, CH2), 1.54 (s, 12H, Me2C). IR (νCO, cm-1): 2004(s), 1950(s), 1933(s), 1910(m). 8: mp 127-128 °C. Anal. Calcd for C32H32N2O4Ru2: C, 54.08; H, 4.54; N, 3.94. Found: C, 54.03; H, 4.42, N, 4.01. 1H NMR (CDCl3) δ: 8.50 (d, J ) 3.00 Hz, 2H, C5H4N), 7.53-7.48 (m, 2H, C5H4N), 7.13-7.09 (m, 2H, C5H4N), 6.85(d, J ) 8.40 Hz, 2H, C5H4N), 5.12 (t, 4H, C5H4), 4.79 (t, 4H, C5H4), 2.98 (s, 4H, CH2), 1.35 (s, 12H, Me2C). IR (νCO, cm-1): 1938(s), 1906(m), 1763(s), 1736(m). 9: mp 175 °C (dec). Anal. Calcd for C38H38N2O4Ru3: C, 51.12; H, 4.29; N, 3.14. Found: C, 51.10; H, 4.33, N, 3.10. 1H NMR (CDCl3) δ: 7.45 (d, J ) 7.50 Hz, 1H, C5H3N), 7.17 (t, 1H, C5H3N), 6.84 (d, J ) 7.50 Hz, 1H, C5H3N), 6.78 (t, 1H, C5H3N), 6.68 (d, J ) 7.50 Hz, 1H, C5H3N), 6.18 (d, J ) 6.00 Hz, 1H, C5H3N), 5.47 (br s, 1H, C5H4), 5.31 (br s, 1H, C5H4), 5.27 (br s, 1H, C5H4), 5.18 (br s, 1H, C5H4), 4.47 (m, 1H, C5H4), 4.44 (m, 1H, C5H4), 4.33 (m, 2H, C5H4), 2.73 (s), 2.68 (s), 2.62 (s), 2.57 (s) (total, 4H, CH2), 2.05-1.92 (m, 2H, (CH2)5), 1.70-1.00 (m, 18H, (CH2)5). IR (νCO, cm-1): 1999(s), 1956(s), 1936(s), 1909(s). 10: mp 202-203 °C. Anal. Calcd for C38H40N2O4Ru2: C, 57.57; H, 5.09; N, 3.54. Found: C, 57.89; H, 4.99, N, 3.60. 1H NMR (CDCl3) δ: 8.43 (d, 2H, J ) 4.80 Hz, C5H4N), 7.44-7.39 (m, 2H, C5H4N), 7.06-7.02 (m, 2H, C5H4N), 6.63(d, 2H, J ) 7.80 Hz, C5H4N), 4.94 (t, 4H, C5H4), 4.70 (t, 4H, C5H4), 3.08 (s, 4H, CH2), 1.951.26 (m, 20H, (CH2)5). IR (νCO, cm-1): 1958(s), 1930(w), 1767(s), 1728(w). Reactions of 4 and 6 with I2. A solution of 0.837 g (1.35 mmol) of 4 and 0.344 g (1.35 mmol) of I2 in 20 mL of CH2Cl2 was stirred for 12 h at room temperature. The solution was washed with saturated Na2S2O3 solution and water in turn and dried over anhydrate Na2SO4. After removal of solvent under reduced pressure, the residue was placed in an Al2O3 column. Elution with acetone developed a yellow band, which gave 0.300 g (25%) of 11 as yellow crystals. Similarly, reaction of 6 with I2 gave 12 in 28% yield. 11: mp 155 °C (dec). Anal. Calcd for C16H16FeINO2: C, 43.97; H, 3.69, N, 3.21. Found: C, 43.92; H, 3.78; N, 3.18. 1H NMR (CDCl3) δ: 8.60 (br s, 1H, C5H4N), 7.88 (m, 1H, C5H4N), 7.63 (m, 1H, C5H4N), 7.28 (br s, 1H, C5H4N), 6.10 (s, 2H, C5H4), 4.88 (s, 2H, C5H4), 3.32 (s, 2H, CH2), 1.33 (s, 6H, Me2C). IR (νCO, cm-1): 2050(s), 2018(s). 12: mp 165 °C (dec). Anal. Calcd for C19H20-

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Table 1. Crystal Data and Summary of X-ray Data Collection for 3, 7, 12, and 13 formula fw T, K radiation (λ), Å cryst syst space group a, Å b, Å c, Å R, deg β, deg γ, deg V, Å3 Z Dcalc, g‚cm-3 µ, mm-1 F(000) cryst size, mm 2θ range, deg no. of reflns collected no. of indep reflns/Rint no. of params goodness-of-fit on F2 R1, wR2 [I > 2σ(I)] R1, wR2 (all data)

3

7

12

13

C19H15Fe2NO5 449.02 293(2) Mo KR orthorhombic Pnma 10.477(7) 9.756(6) 18.071(11) 90 90 90 1847(2) 4 1.615 1.600 912 0.14 × 0.12 × 0.06 4.50-53.18 10 057 2025/0.0813 169 1.108 0.0629, 0.1284 0.1023, 0.1443

C32.5H31ClN2O4Ru3 852.25 293(2) Mo KR triclinic P1h 9.315(3) 12.751(5) 14.097(5) 96.156(5) 108.847(6) 92.507(6) 1570.1(10) 2 1.803 1.549 842 0.24 × 0.22 × 0.18 3.22-52.86 9229 6396/0.0182 401 1.066 0.0315, 0.0711 0.0506, 0.0862

C19H20FeINO2 477.11 293(2) Mo KR orthorhombic P2(1)2(1)2(1) 7.987(2) 14.590(4) 16.197(5) 90 90 90 1887.4(10) 4 1.679 2.445 944 0.22 × 0.14 × 0.14 3.76-50.02 9763 3325/0.0455 217 1.076 0.0406, 0.0966 0.0673, 0.1058

C15H16INORu 454.26 293(2) Mo KR triclinic P1h 8.471(4) 9.095(5) 11.059(6) 84.051(9) 87.122(9) 62.536(7) 751.9(7) 2 2.006 3.087 436 0.32 × 0.26 × 0.20 5.06-50.02 3869 2619/0.0178 174 1.088 0.0234, 0.0546 0.0331, 0.0587

FeINO2: C, 47.83; H, 4.23, N, 2.94. Found: C, 47.68; H, 4.36; N, 2.80. 1H NMR (CDCl3) δ: 8.73 (br s, 1H, C5H4N), 7.80 (m, 1H, C5H4N), 7.51 (m, 1H, C5H4N), 7.22 (br s, 1H, C5H4N), 5.92 (s, 2H, C5H4), 4.91 (s, 2H, C5H4), 3.21 (s, 2H, CH2), 1.56-1.18 (m, 10H, (CH2)5C). IR (νCO, cm-1): 2044(s), 1983(m). Reactions of 8 and 10 with I2. Using a procedure similar to that described above, reactions of 8 and 10 with I2 gave 13 and 14 in 59% and 31% yields, respectively. 13: mp 180 °C (dec). Anal. Calcd for C15H16INORu: C, 39.57; H, 3.54, N, 3.08. Found: C, 39.90; H, 3.70; N, 3.04. 1H NMR (CDCl3) δ: 9.27 (br s, 1H, C5H4N), 7.60 (t, 1H, C5H4N), 7.24 (d, J ) 7.50 Hz, 1H, C5H4N), 7.01 (t, 1H, C5H4N), 5.38 (s, 1H, C5H4), 5.05 (s, 1H, C5H4), 4.55 (s, 1H, C5H4), 4.46 (s, 1H, C5H4), 3.15 (d, J ) 14.4 Hz, 1H, CH2), 2.84 (d, J ) 14.4 Hz, 1H, CH2), 1.38 (s, 3H, Me2C), 1.00 (s, 3H, Me2C). IR (νCO, cm-1): 1931(s). 14: mp 183-184 °C. Anal. Calcd for C18H20INORu: C, 43.64; H, 4.07, N, 2.83. Found: C, 43.50; H, 4.05; N, 2.74. 1H NMR (CDCl3) δ: 9.22 (br s, 1H, C5H4N), 7.60 (t, 1H, C5H4N), 7.31 (d, J ) 7.50 Hz, 1H, C5H4N), 7.01 (t, 1H, C5H4N), 5.44 (s, 1H, C5H4), 4.94 (s, 1H, C5H4), 4.60 (s, 1H, C5H4), 4.53 (s, 1H, C5H4), 3.19 (d, J ) 14.1 Hz, 1H, CH2), 2.98 (d, J ) 14.1 Hz, 1H, CH2), 1.57-1.23 (m, 10H, (CH2)5C). IR (νCO, cm-1): 1938(s).

Crystallographic Studies. Crystals of complexes 3, 4, 7, 8, 12, and 13 suitable for X-ray diffraction were investigated with a Bruker SMART 1000 diffractometer, using graphite-monochromated Mo KR radiation (ω-2θ scans, λ ) 0.71073 Å). Semiempirical absorption corrections were applied for all complexes. The structures were solved by direct methods and refined by full-matrix leastsquares. All calculations were done using the SHELXL-97 program system. The crystal data and summary of the X-ray data collection for complexes 3, 7, 12, and 13 are presented in Table 1.

Acknowledgment. We are grateful to the National Natural Science Foundation of China (20202004, 20421202, 20472034), the Research Fund for the Doctoral Program of Higher Education of China (20030055001), and the Program for New Century Excellent Talents in University for financial support. Supporting Information Available: X-ray structural information for complexes 3, 4, 7, 8, 12, and 13, including the ORTEP figures of 4 and 8. This material is available free of charge via the Internet at http://pubs.acs.org. OM050684P